Arsène Wenger is relying on players returning from long-term injuries to be de facto new signings. Photograph: Paul Childs/Action Images

Guardian writers' prediction: 5th Odds to win league: 8-1

Last season was only one game old when Arsène Wenger felt the first jabs of the pressure that would follow him throughout what turned out to be his most punishing campaign. The post-match inquisition evidently wasn't too interested in the details of a mundane 1-0 win over West Bromwich Albion and went straight to the heart of the matter: how many more seasons can you go without a trophy, Arsène? How can you sell some of your best players and seriously expect to win a trophy, Arsène? Can you really go four years at a club like this without a trophy, Arsène?

The man's expression stiffened. The season's record at the time was played one, won one. It seemed a bit harsh to be under the cosh and talking about bloody trophies already.

Then came game No2. Fulham 1-0 Arsenal. Wenger's team were abominable. Robin van Persie remembers sitting on the coach afterwards feeling completely shell-shocked. In a sense, Arsenal's campaign never really recovered. The basic frailties in the squad, the ones you don't need to be Alan Hansen to pinpoint, always had the capacity to trip them up.

As the new season comes over the horizon, Wenger finds himself in a similar position to a year ago. He knows the trophy question is even more pressing. He is perfectly aware that Manchester City's new collection puts a top four position at greater risk than ever before. But if you think that will drag him into buying a job lot of monsters to do the team's dirty work, you underestimate his exceptional bloody-mindedness.

And, to an extent, his optimism. He is relying on those returning from long-term injuries, Eduardo and Tomas Rosicky, to be de facto new signings. Banking on them staying fit, and playing better than ever before, is a major gamble. So too is his faith in the likes of Denilson, Alex Song, Abou Diaby and Aaron Ramsey to be a year older and wiser in midfield. But that seems to be the plan. Incidentally, there is an interesting statistic in the Gooner fanzine's annual survey: some 93% of fans polled don't think the current squad can win the title without any major signings.

Wenger has made one fairly important adjustment to his strategy for 2009-10. He appears to have had a Eureka moment. It didn't come from a team who do what Arsenal can't – such as the power play Chelsea rediscovered under Guus Hiddink, the clean sheets ground out by Manchester United's impeccable defensive partnership, or the dynamics Javier Mascherano and Xabi Alonso brought to Liverpool's midfield. It came from the team who do what Arsenal think they can do, only they do it much better: Barcelona.

Wenger has come to the conclusion that shape, not personnel, will be the key to a big improvement. Once a strict 4-4-2 man, he has been dabbling increasingly with a 4-5-1 over the past couple of years, but that was always with five midfielders strung across the pitch. Throughout pre-season Wenger has shifted it to a 4-3-3. He has plenty of options for his attacking trio, with Van Persie, Nicklas Bendtner, Andrey Arshavin, Eduardo, Theo Walcott and Carlos Vela all in contention. A Barcelona-style passing game, with a bit more bite up front than Wenger's usual deviation from 4-4-2, is the new formula.

The irony is that the two players he has sold to Manchester City, Emmanuel Adebayor and Kolo Touré, offered outlets that could give Arsenal variation from their tippy-tappy possession game, either through a high ball to Adebayor or one of Touré's cavalier runs upfield from the back.

But it's hard to argue that the sales are anything but magnificent business financially, and Wenger genuinely believes those two will barely be missed - both inside the dressing room, where they were part of a clique - as well as on the pitch, where last season neither performed as well as they had in the past.

Regulars at Emirates Stadium back the manager on those departures, provided the money is invested back into the team pronto. They pay for the most expensive tickets in football, and want to see a competitive team, not a competitive balance sheet. They do not want to see more of the defensive vulnerability that is Arsenal's undoing but they ought not hold their breath.

For the time being, they just have to wait to see if Wenger will use the Manchester City money on some Mongolian wunderkind or if he will surprise them and lay out for the finished article. Will he buy a massive, ugly defender? Might he bring in an experienced, midfield destroyer to dovetail with Cesc Fábregas? Could he inject a little more of the calibre of Arshavin that made such a difference to the team?

They will almost certainly have to wait until the closing seconds of the transfer window, Wenger's usual trading time, to find out.